The invention concerns butterfly valve seals, and more particularly, an improved butterfly valve having a mechanically retained seat.
Butterfly valves have been used for many years for precise flow control in fluid applications. Fluid tight shut-off has been achieved with a rubber or similar type seat in the valve body and a steel ring on the disc. The rubber seat is usually bonded to the valve body or retained by bolts inserted into the body through the seat.
It has been the experience working with such prior art seat arrangements that they require extensive labor to fabricate and assemble. Further, field replacement or adjustment caused problems or were not able to be done. Also, some bonded seats failed under high flow conditions.
In order to overcome the foregoing and other problems with the prior art, an object of the invention is to provide an improved butterfly valve seal arrangement which has a mechanically retained seat, simple to fabricate and assemble, and is field replaceable and adjustable.